后台静音返回为时过早

Question

我创建了一个按钮，该按钮可在播放另一个剪辑时使在后台运行的音频静音，但是，如果我按“取消”按钮以停止播放该音频文件并播放另一个，则它将继续运行上一个按钮上关联的代码。有些按钮的音频文件比其他按钮长，所以我试图找到一种取消代码background.volume = 2的方法，但是我没有运气，有人能找出解决方法或取消该方法的方法吗？退出先前的代码请求？

@IBAction func AudioSet1(_ sender: Any) {
    NSObject.cancelPreviousPerformRequests(withTarget: DispatchQueue.main)
    if ResetAction.isEnabled == true {
    let AudioSet1 = URL(fileURLWithPath: Bundle.main.path(forResource: "AudioSet1", ofType: "mp3")!)
    do {
        audioPlayer = try
            AVAudioPlayer(contentsOf: AudioSet1)
        audioPlayer.prepareToPlay()
    } catch {
        print("File load error #5")
    }
    audioPlayer.play()
    audioPlayer.volume = 2
    background.volume = 0
    self.ResetAction.isEnabled = false
    if audioPlayer.isPlaying{
        do{
        DispatchQueue.main.asyncAfter(deadline: .now() + 16.5) {
            self.background.volume = 2
            self.ResetAction.isEnabled = true
            }}}}
}

 @IBAction func AudioSet2(_ sender: Any) {
    NSObject.cancelPreviousPerformRequests(withTarget: DispatchQueue.main.suspend())
    if ResetAction.isEnabled == true {
    let AudioSet2 = URL(fileURLWithPath: Bundle.main.path(forResource: "AudioSet2", ofType: "mp3")!)
    do {
        audioPlayer = try
            AVAudioPlayer(contentsOf: AudioSet2)
        audioPlayer.prepareToPlay()
    } catch {
        print("File load error #3")
    }
    audioPlayer.play()
    audioPlayer.volume = 2
    self.ResetAction.isEnabled = false
    if audioPlayer.isPlaying{
            self.background.volume = 0
        do {
        DispatchQueue.main.asyncAfter(deadline: .now() + 27){
            self.background.volume = 2
            self.ResetAction.isEnabled = true
            }}}}
}

那是音频按钮，这是清除按钮，我想要在其中取消代码的asyncAfter部分：

`@IBAction func Reset(_ sender: Any) {
    if background.volume == Float(0){
        NSObject.cancelPreviousPerformRequests(withTarget: DispatchQueue.main.self)
    }
    let AudioRender = URL(fileURLWithPath: Bundle.main.path(forResource: "", ofType: "mp3")!)
    do {
        audioPlayer = try
            AVAudioPlayer(contentsOf: AudioRender)
        audioPlayer.prepareToPlay()
    } catch {
        print("File load error #1")
    }
    audioPlayer.play()
    audioPlayer.volume = 0
    background.volume = 2
    self.ResetAction.isEnabled = true
}`

谢谢